1. Field
The present invention relates to a secondary battery.
2. Description of the Related Art
Unlike primary batteries which are not designed to be recharged, secondary batteries are designed to be repeatedly charged and discharged. Low-capacity secondary batteries, each using a single battery cell packaged in a battery pack, are widely employed in small-sized portable electronic devices, such as cellular phones or camcorders, while large-capacity secondary batteries, each using tens of battery cells connected to each other in a battery pack, are typically used for driving motors of hybrid automobiles or the like.
Secondary batteries may be manufactured in various shapes, including cylindrical and prismatic shapes. The prismatic secondary battery may generally include an electrode assembly, a case accommodating the electrode assembly with an electrolyte, electrode terminals electrically connected to the electrode assembly and exposed or protruding to outside of the case, and terminal plates electrically connected to the electrode terminals on a cap plate.
Prismatic secondary batteries may be mounted in a vehicle in a state in which the terminal plates of adjacent secondary batteries are connected to each other through a bus bar. In this case, the terminal plates may rotate or vibrate due to vibration of the vehicle, and an external force may be applied to the cap plate by the rotation or vibration of the terminal plates resulting in physical deformation, such as warp or distortion. When a short-circuit plate is installed in the cap plate to induce an electric short during overcharge of the secondary battery, the short-circuit plate may also become unintentionally deformed, thereby considerably lowering safety of the secondary battery.